Thermo Fisher Agrees to Sell Microbiology Business to Astorg for $1.075 Billion

Thermo Fisher Scientific has signed a definitive agreement to sell its microbiology business to private equity firm Astorg for about $1.075 billion, made up of cash and a $50 million seller note, the company announced on April 27, LabMedica reported.

The business sells antimicrobial susceptibility testing and culture media for clinical, pharmaceutical and food safety use, and generated $645 million in revenue in 2025, sitting within Thermo Fisher's Specialty Diagnostics segment, according to LabMedica. Microbiology sales grew nearly 2% year over year, MedTech Dive reported.

Deal terms and timing

Thermo Fisher expects the transaction to close in the second half of 2026, subject to customary closing conditions and regulatory approvals. The company said the sale is expected to reduce adjusted earnings per share by $0.15 in the first full year after closing, and that it will give more detail on the effect on its 2026 financial outlook on its second-quarter earnings call, according to LabMedica.

"The transaction reflects our active management of the company and provides additional capital we can deploy to create shareholder value," Marc N. Casper, Thermo Fisher's chairman and chief executive, said in the announcement, as quoted by LabMedica. "We believe the microbiology business is an excellent fit within Astorg’s portfolio."

What Astorg is buying

Microbiology is one of five primary businesses in Thermo Fisher's specialty diagnostics segment, MedTech Dive reported. The unit sells culture media, collection and transport systems, instruments and consumables to detect pathogens in blood, specimen tests, and quality-control products, according to the publication.

The business has about 2,400 employees and operates 13 manufacturing and research and development sites worldwide. More than 95% of its revenue is recurring, from roughly 15,000 customers who run more than 38,000 labs in over 100 countries, MedTech Dive reported.

Astorg plans to run the business as an independent, privately owned platform and to work with its leadership team to scale it, with a focus on accelerating growth and improving operational performance, according to MedTech Dive. The firm has said acquisitions are part of its plans for the business and has pointed to trends such as rising quality control requirements in the pharmaceutical industry, the publication reported.

In clinical microbiology, the unit competes with companies including bioMérieux, which said it had a 40% share of that sector in 2024, as well as Waters and Danaher, MedTech Dive reported. Waters acquired microbiology products in its takeover of BD's biosciences business, according to the publication.